Abu Hurayra said,
“The Prophet was asked, ‘Messenger of Allah, to whom should I be dutiful?’ ‘Your mother,’ he replied. He was asked, ‘Then whom?’ ‘Your mother,’ he replied. He was asked, ‘Then whom?’ ‘Your mother,’ he replied. He was asked, ‘Then whom?’ He replied, ‘Your father.'”
[Al-Adab Al-Mufrad Book 1 Hadith 5]